In traditional liquid crystal display technologies, for improving the stability of an oxide TFT (thin film transistor) in a dual-gate TFT array substrate, an etch stop layer (ESL) structure is widely adopted, and the structure can efficaciously decrease influences for back channels from external environment factors and etching damages of source and drain electrodes.
In an active array display device, a single-gate TFT is commonly adopted. But the dual-gate TFT has the advantages of: higher mobility, greater on-state current, smaller threshold swing, better threshold voltage stability, better uniformity, and has better gate bias stability.
However, in a manufacturing method of a dual-gate TFT array substrate of a traditional FFS (fringe field switching) display mode, forming a common electrode and source/drain electrodes each requires one mask (photomask), respectively. Thus, an increased number of masks is required, so that the process complexity and the manufacturing cost are increased, which is disadvantageous to improving the manufacturing efficiency.